1. Field of the Invention
The present invention relates to an electroluminescent display apparatus. In particular, the present invention relates to an electroluminescent display apparatus having a substrate structure capable of facilitating measurement of a width of a sealant employed thereon.
2. Description of the Related Art
In general, an electroluminescent display apparatus may refer to a thin, light display device, such as an organic light emitting display device. The conventional electroluminescent display apparatus may include a display unit with a plurality of light emitting diodes positioned on a substrate.
Additionally, the conventional electroluminescent display apparatus may include a sealing substrate to protect the light emitting diodes from degradation caused by an oxidation, i.e., an interaction with oxygen from indium-tin-oxide (ITO) used in electrodes, a reaction between interfaces of light emitting layers, or by external impurities, e.g., moisture, oxygen, ultraviolet rays, manufacturing conditions, and so forth. The sealing substrate may be attached to the substrate by a sealant to enclose the display unit therebetween. The conventional sealant 80, as illustrated in FIG. 1, may include spacers 82 in an adhesive 81 to minimize compression of the display unit 20 and maintain a predetermined distance between the substrate 10 and the sealing substrate (not shown).
Application of the sealant 80 to the electroluminescent display apparatus may involve consideration of a width thereof. More specifically, the sealant 80 should be sufficiently wide to prevent penetration of external impurities therethrough. On the other hand, an excessive width of the sealant 80 may trigger sealant penetration into the display unit and cause a malfunction thereof. Accordingly, the width of the sealant 80 may be evaluated to provide proper operation of the electroluminescent display apparatus.
However, the width of the conventional sealant 80 employed in the conventional electroluminescent display apparatus is often evaluated by the naked eye upon attaching the substrate 10 with the sealing substrate. More importantly, the conventional sealant 80 may be transparent, thereby triggering measuring errors regarding the width thereof. Consequently, the width of the conventional sealant 80 in the conventional electroluminescent display apparatus may not be correctly measured and applied, thereby generating potential malfunctioning of the display unit.
Accordingly, there exists a need to provide an electroluminescent display apparatus having a structure capable of facilitating measurement of the sealant width employed therein.